luxrender gpu render farm
You can try to set it up via the network renderer addon. But if that's no option for you you could try different things.
if you use windows
You can control Blender via the command-shell. That means that you can do it with a short batch file as well. You will need 3 batch files for that:
setup-client
this file is optional but it makes things a lot easier. It asks for the parameters like start frame, end frame etc. .write it on the master-computer.
manager
the manager is a short program that distributes single frames to the seperate render clients and uploads the file together with the parameters to an ftp-server (or a public drive). this program normally runs on the master computer as well.
render client
This program starts blender with the parameters submitted by the manager in the GPU rendering mode. An advanced feature would be to make it restart outomaticly if Blender crashes during rendering.
if you use Mac, Linux or Windows
Create an custom addon for Blender that replaces the batch files.